Crude and multivariable associations of economic and educational position with infants' outcomes among the ALSPAC and Pelotas birth cohort studies
| Models | Relative index of inequality: OR for each outcome comparing those at the bottom to those at the top of the income or educational hierarchy (95% CI) | |||||||
| Income | Education | |||||||
| ALSPAC 1991/92 | Pelotas 1982 | Pelotas 1993 | Pelotas 2004 | ALSPAC 1991/92 | Pelotas 1982 | Pelotas 1993 | Pelotas 2004 | |
| Intra-uterine growth restriction | ||||||||
| Crude | 2.2 (1.7 to 2.8) | 3.3 (2.5 to 4.2) | 2.0 (1.5 to 2.6) | 2.3 (1.7 to 3.1) | 2.0 (1.6 to 2.4) | 2.2 (1.7 to 2.9) | 2.2 (1.6 to 3.0) | 1.9 (1.4 to 2.6) |
| Model 1 | 2.2 (1.7 to 2.8) | 3.5 (2.6 to 4.6) | 2.0 (1.5 to 2.7) | 2.3 (1.7 to 3.2) | 2.0 (1.6 to 2.5) | 2.5 (1.8 to 3.3) | 2.2 (1.6 to 3.1) | 2.2 (1.6 to 3.0) |
| Model 2 | 2.0 (1.5 to 2.7) | 3.7 (2.7 to 5.1) | 2.0 (1.5 to 2.7) | 2.5 (1.8 to 3.5) | 2.3 (1.8 to 3.0) | 2.6 (1.9 to 3.5) | 2.2 (1.6 to 3.1) | 2.9 (2.0 to 4.2) |
| Model 3 | 1.7 (1.2 to 2.3) | – | 1.9 (1.4 to 2.6) | 2.5 (1.8 to 3.5) | 2.1 (1.6 to 2.7) | – | 2.1 (1.5 to 3.0) | 3.0 (2.0 to 4.3) |
| Model 4 | 1.4 (1.0 to 1.9) | 3.5 (2.5 to 4.7) | 1.7 (1.3 to 2.4) | 2.2 (1.6 to 3.1) | 1.7 (1.3 to 2.2) | 2.4 (1.8 to 3.4) | 1.8 (1.3 to 2.6) | 2.5 (1.7 to 3.6) |
| Model 4+SEP score | 1.2 (0.8 to 1.7) | 3.1 (2.1 to 4.6) | 1.5 (1.1 to 2.1) | 1.8 (1.3 to 2.6) | 1.8 (1.3 to 2.6) | 1.2 (0.8 to 1.8) | 1.6 (1.1 to 2.3) | 2.0 (1.3 to 3.0) |
| Preterm birth | ||||||||
| Crude | 1.8 (1.3 to 2.6) | 1.3 (0.8 to 2.0) | 1.6 (1.2 to 2.2) | 2.4 (1.7 to 3.3) | 1.6 (1.2 to 2.1) | 1.3 (0.8 to 2.1) | 1.9 (1.3 to 2.6) | 2.3 (1.6 to 3.2) |
| Model 1 | 1.8 (1.2 to 2.6) | 1.1 (0.7 to 1.8) | 1.6 (1.1 to 2.1) | 2.1 (1.5 to 2.9) | 1.6 (1.1 to 2.2) | 1.3 (0.8 to 2.1) | 1.9 (1.4 to 2.7) | 2.2 (1.6 to 3.2) |
| Model 2 | 1.8 (1.2 to 2.8) | 1.1 (0.6 to 1.9) | 1.3 (1.0 to 1.9) | 1.9 (1.3 to 2.8) | 1.6 (1.1 to 2.3) | 1.1 (0.6 to 1.9) | 1.6 (1.1 to 2.3) | 2.3 (1.5 to 3.4) |
| Model 3 | 1.6 (1.0 to 2.6) | – | 1.2 (0.8 to 1.7) | 1.8 (1.2 to 2.5) | 1.2 (0.8 to 1.9) | – | 1.4 (1.0 to 2.1) | 2.2 (1.4 to 3.3) |
| Model 4 | 1.7 (1.1 to 2.9) | 1.1 (0.6 to 1.8) | 1.2 (0.8 to 1.7) | 1.7 (1.2 to 2.4) | 1.3 (0.8 to 1.9) | 1.1 (0.6 to 1.8) | 1.4 (1.0 to 2.0) | 2.0 (1.3 to 3.1) |
| Model 5 | 1.7 (1.0 to 2.9) | 1.1 (0.7 to 1.9) | 1.2 (0.9 to 1.8) | 1.7 (1.2 to 2.5) | 1.2 (0.8 to 1.9) | 1.1 (0.6 to 1.9) | 1.5 (1.0 to 2.1) | 2.0 (1.3 to 3.1) |
| Model 6 | 1.7 (1.0 to 2.8) | 1.3 (0.8 to 2.3) | 1.3 (0.9 to 1.8) | 1.8 (1.2 to 2.6) | 1.2 (0.8 to 2.0) | 1.2 (0.7 to 2.2) | 1.5 (1.0 to 2.2) | 2.2 (1.4 to 3.4) |
| Model 6+SEP score | 1.7 (1.0 to 3.0) | 1.2 (0.6 to 2.5) | 1.1 (0.8 to 1.6) | 1.5 (1.0 to 2.3) | 0.9 (0.5 to 1.7) | 1.1 (0.5 to 2.2) | 1.4 (1.0 to 2.2) | 1.9 (1.2 to 3.0) |
| Breast feeding for less than 3 months | ||||||||
| Crude | 3.4 (2.8 to 4.1) | 1.1 (0.7 to 1.6) | 0.9 (0.6 to 1.4) | 1.6 (1.2 to 2.1) | 6.9 (5.8 to 8.3) | 0.8 (0.5 to 1.2) | 1.2 (0.8 to 1.9) | 1.8 (1.4 to 2.4) |
| Model 1 | 3.3 (2.7 to 4.0) | 1.1 (0.7 to 1.6) | 0.9 (0.6 to 1.4) | 1.5 (1.1 to 1.9) | 6.6 (5.5 to 8.0) | 0.9 (0.6 to 1.4) | 1.3 (0.8 to 2.0) | 1.7 (1.3 to 2.4) |
| Model 2 | 3.0 (2.4 to 3.7) | 1.2 (0.8 to 2.0) | 0.9 (0.6 to 1.4) | 1.3 (1.0 to 1.8) | 6.6 (5.4 to 8.1) | 0.9 (0.6 to 1.5) | 1.5 (0.9 to 2.5) | 1.8 (1.3 to 2.5) |
| Model 3 | 3.1 (2.5 to 3.8) | – | 0.9 (0.5 to 1.4) | 1.3 (0.9 to 1.7) | 7.0 (5.6 to 8.6) | – | 1.5 (0.9 to 2.5) | 1.8 (1.3 to 2.6) |
| Model 4 | 2.6 (2.0 to 3.2) | 1.1 (0.7 to 1.8) | 0.8 (0.5 to 1.3) | 1.2 (0.9 to 1.7) | 6.1 (4.9 to 7.6) | 0.9 (0.6 to 1.4) | 1.4 (0.8 to 2.3) | 1.7 (1.2 to 2.5) |
| Model 5 | 2.5 (2.0 to 3.2) | 1.1 (0.7 to 1.8) | 0.8 (0.5 to 1.2) | 1.2 (0.9 to 1.7) | 6.3 (5.0 to 7.9) | 0.9 (0.5 to 1.4) | 1.3 (0.8 to 2.1) | 1.7 (1.2 to 2.5) |
| Model 6 | 2.5 (2.0 to 3.2) | 1.1 (0.6 to 1.9) | 0.8 (0.5 to 1.2) | 1.2 (0.9 to 1.6) | 6.2 (4.9 to 7.7) | 0.8 (0.5 to 1.3) | 1.3 (0.8 to 2.1) | 1.7 (1.2 to 2.5) |
| Model 7 | 2.5 (2.0 to 3.2) | 1.1 (0.6 to 1.9) | 0.8 (0.5 to 1.2) | 1.2 (0.9 to 1.6) | 6.1 (4.9 to 7.7) | 0.8 (0.5 to 1.3) | 1.2 (0.7 to 2.0) | 1.7 (1.2 to 2.4) |
| Model 7+SEP score | 1.4 (1.1 to 1.8) | 1.7 (0.8 to 3.5) | 0.7 (0.4 to 1.1) | 1.0 (0.7 to 1.4) | 5.7 (4.3 to 7.4) | 0.6 (0.3 to 1.2) | 1.4 (0.8 to 2.5) | 1.7 (1.2 to 2.5) |
Model 1: adjusted for pre-pregnancy body mass index.
Model 2: Model 1+ethnic origin, maternal age, marital status and parity.
Model 3: Model 2+urinary infection, hypertension, hospital admission during pregnancy.
Model 4: Model 3+ever smoked during pregnancy for the ALSPAC and Pelotas 1993 and 2004; Model 2+ever smoked during pregnancy for the Pelotas 1982 cohort study.
Model 5: Model 4+caesarean section and delivery assisted by doctor.
Model 6: Model 5+intra-uterine growth restriction.
Model 7: Model 6+preterm birth.
SEP, socioeconomic position.